Switch



D. T. SIEGEL June 23, 1936.

SWITCH Filed Dec. 31.

Patented June 23, 1936 UNITED STATES SWITCH David T. Siegel, Chicago, Ill.

Application December 31,

1934, Serial No. 759,927

4 Claims. ((31. 200-43) My invention relates to electric switches, and particularly to a novel form of multiple switch and to the method of constructing it.

In electric apparatus of different forms, it is desirable or necessary to provide a multiple switch; that is, a switch having a terminal connected to a movable switch arm and a plurality of terminals adapted to be contacted in sequence by the switch arm. Such a device is here described, and the construction and the method by which it is constructed are novel in many particulars.

For example, in a preferred form, I provide a base composed of ceramic material such as porcelain, the base having a seat, and a core also composed of ceramic material adapted to be permanently mounted on the base. Arranged in spaced relation on the core are a plurality of terminals, each in the form of a band surrounding the core, an end of the band serving as a means of connection to an electrical conductor, while the upper portion of the band serves as a contact member for a swinging switch arm. In a preferred form of the construction, the bands are assembled in properly spaced relation on the core and the overlapping ends are welded, brazed, or otherwise permanently joined, whereby the bands are firmly clamped in place. Thereafter, the base and core with its assembled terminal bands are dipped in, or otherwise coated with, a vitreous enamel and the parts placed in an oven for the vitrifying of the enamel and the permanent joining of the core and base. Thereafter, any enamel is removed from the top surface of the bands to provide a good contact surface for the switch arm.

It will be noted also that I prefer to utilize as a part of the switch arm a separate brush mounted for limited universal movement, the brush being composed of a metal-impregnated graphite. The advantage in the use of such construction is that the brush readily adjusts itself to inaccuracies in the surface planes of the contacts,

- and the use of the metal-impregnated graphite serves to avoid the possibility of welding in the event of excessive arcing.

Other features of construction and the advantages inherent therein will be discussed in the following description.

The invention will be more readily understood by reference to the accompanying drawing, in which:

Fig. switch constructed vention;

in accordance with my in- 1 is a view of the rear face of a multiple- Fig. 2 is a sectional view on the irregular line 2-2 of Fig. 1, and

Fig. 3 is a fragmentary sectional view on the line 3-3 on Fig. 1.

In the drawing, I have illustrated the switch as including a base ill of generally circular outline, having a seat H formed therein and a central cavity or recess l2. Associated with the base is an arcuate core l3 shaped to cooperate with the seat |l,both the base and the core preferably being compo ed of ceramic material, such as porcelain.

In the process of manufacture, I provide bands ll that are looped around the core at evenly spaced intervals. Six of such bands are shown in the drawing, although it will be understood that a smaller or greater number will be pro vided, according to the intended use of the switch.

' The bands are tightly clamped around the core and the overlapping ends are permanently joined, as at I5, by welding, brazing, or otherwise. The terminal portions I6 of the bands constitute the means for connection of wires. 1

After the bands are assembled as described, the seat and adjacent surface of the base and the entire surface of the core and assembled bands are coated with a. vitreous enamel slip, the core is temporarily held in place on the base and the parts placed in a baking oven for the vitrifying of the enamel. After this step is completed, any enamel adhering to the upper surfaces ll of the bands is removed by grinding, thereby providing smooth contact faces for the switch arm and brush. The enamel coating for the various parts is indicated at IS in Fig. 2.

The multiple switch may be either of the commutator type or the snap action type. In the snap action type, such as disclosed herein, the contact pieces will be separated and the snap action may be secured by providing rather abrupt elevations l9 between the adjacent contact pieces. These elevations are formed as a part of the porcelain core and will be coated with a vitreous enamel in the process of manufacture. In. this construction, the bands H occupy notches formed in theupper surface of the core at the ends of the elevations l9.

The switch arm is operatedby a shaft 28 having a knob 22 thereon. The arm. is directly moved by means of the insulated sleeve 28 that is held against angular movement on the shaft 2i by means of the pin 2. The projections 25 on the sleeve engage corresponding notches on to effect movement in unison. 28 is in the form of a resilient the switch arm The switch arm loop, its backwardly-bent inner end surrounding the sleeve 23 and lying against a washer 29. The washer in turn contacts a terminal piece 25, the inner end of which is perforated to admit the insulated sleeve 23 while the outer end provides for a wire connection. meets the washer to the contact brush This brush is a small section of material 00.1. posed of graphite and impregnated metal, a substantial percentage of graphite serving the useful purpose of avoiding welding of the brush to the contacts and insuring a smooth and easy surface engagement of the moving parts. The brush is held within a cup formed on the end of the contact arm 2@, and a rivet Bil having a rounded head provides the contact point between the brush and the arm. This enables the brush to adjust itself to any irregularities on the contacting surfaces and to ride with ease over the elevations intervening between the adjacent contacts. The flexible connection for the'brush enables this universal movement and insures complete electric contact regardless of the position of the brush relative to the arm that holds it.

One of the important advantages in the arrangement shown is in the ease and facility with which the ceramic base and core are coated with a vitreous enamel and halted in a subsequent treatment. The upper surface of'the base is covered with the enamel slip, then the core is coated and any excess enamel removed from the upper surfaces of the bands in the notches; then the core is placed in the seat provided in the base and pressed in place. The excess enamel flows around the joint between the core and base and insures a thorough union between the two parts when the enamel is vitrified. The base may then be placed in the oven, resting on its face, and the vitrifying action. completed. The unit as thus completed has the terminal bands thoroughly embedded in the enamel and firmly joined to the core and base.

In operation, the various terminals being connected to the respective wires, the switch arm is moved as desired into the-various angular positions permitted. A stop member in the form cl a pin 30 is provided on the shaft it, a stop 32 forming a part of the assembly. This arrangement is of advantage, as it avoids the necessity for stop provisions on the exterior of the switch structure.

A flexible element 2'1! con-' to snap into and out of contact aoeaair I claim: 1. In a multiple switch, the combination of a base having a seat, a core of circular outline adapted to cooperate with the seat. said base and core being composed of ceramic material, a, plurality of bands around said core and arranged in angularly spaced relation and providing terminals, fused vitreous enamel uniting said core and base and embedding said bands except as to the surfaces thereof on the top edge oi the core, a switch arm adapted to progressively contact said exposed surfaces, and means for pro= viding a snap action of the switch arm between adjacent contacts, said means including eleva tions overlaid with said enamel.

2. In combination, a base, a core mounted thereon, terminal bands surrounding the core and arranged in angularly spaced relation there on, said core having elevations between adjacent bands, fused vitreous enamel covering said elevations, a shaft and a spring switch connected thereto, said arm being adapted to ride over the elevations between adjacent bands and to snap into and out of contact with the bands as the result thereof.

3. in combination, a base, a core mountedthereon, terminal bands surrounding the core and arranged in angularly spaced relation thereon, said core having elevations between adjacent bands, fused vitreous enamel covering said elevations, a shaft and a spring switch arm con nected thereto, said arm being adapted to ride over the elevations between adjacent bands and with the bands as the result thereof, and means insulating said shaft from said switch arm.

a. In combination, a base, a core mounted thereon, terminal bands surrounding the core and arranged in angularly spaced relation thereon, said core having elevations between adjacent bands, fused vitreous enamel-covering said elevations, a shaft and a spring switch arm connected thereto, said arm being adapted to ride over the elevations between adjacent bands and to snap into and out of contact with the bands as the. result thereof, a terminal, a brush mounted on said arm with capacity for rocking movement, and a flexible connection between said brush and said last-named terminal.

' DAVE T. SIEGEL. 

